Chevrolet Silverado 1500 / 2500 / 3500:

No Voltage to AC compressor clutch

You are not logged in.

# 1  8/8/2011 1:42 AM

New member
Registered: 8/8/2011
Posts: 1

No Voltage to AC compressor clutch

1992 Chevy 4x4 1500 5.7 engine, I am not getting any voltage to the AC clutch.  Have checked at fuse panel, good there, not getting any voltage at any points in engine compartment, (pressure switch, clutch, etc.)  Was thinking it could possibly be the switch in dash.  Any help greatly appreciated.



# 2  8/8/2011 2:33 PM

Registered: 11/24/2009
Posts: 1301

Re: No Voltage to AC compressor clutch

When an air conditioning mode is selected, voltage is supplied to the compressor clutch. As the compressor reduces the evaporator pressure to approximately 25 psi, the pressure switch will open, de-energizing the compressor clutch. As system equalizes and the pressure reaches approximately 46 psi, the pressure switch contacts close, re-energizing the clutch coil.

Check for voltage at the low pressure switch on the A/C accumulator. Short the two wires on the switch if you have voltage and see if the compressor turns on.

Did you check the A/C clutch relay?

It is located under the I/P (instrument panel) on top of heater-A/C case it appears to be the first relay to the left of the group of three that are there.

Check the voltage at the A/C controller, the wire is 1651 (dark blue white tracer) this wire activates the clutch relay. If there is no power coming from this wire then it may be a bad A/C controller.

If all of these suggestions check out you can try to reset the control module by simply disconnecting the battery for about 30 seconds and then reconnect the battery.

This usually resets the module and will make the compressor work again. Try this it may help.

If you need more assistance we are here to help. Get back to us when you can.
car and truck information like nowhere else


E-mail Page
Print Page
Save or Share Information is the leading source of factory diagnostic & repair information specific to your car.

Powered by PunBB
Copyright © 2007-

Save or Share Automotive Information
Custom Search